The present disclosure relates to a liquid-liquid separation device useful for the separation of a higher density fluid and a lower density fluid. The device is useful for separating water and oil in hydrocarbon production operations. The present disclosure also relates to systems and methods for use of the device.
Compact separators have been developed to replace large, expensive conventional separator vessels used for separating oil, water and gas in hydrocarbon production operations. Such compact separators may be more desirable for offshore use, as they may provide a reduced footprint, and may be lighter, safer and less expensive. An example of such a compact separator is the liquid-liquid cylindrical cyclone (also referred to as the LLCC©, copyright by the University of Tulsa), which includes a vertical pipe with a horizontal inlet. The horizontal inlet includes a reducing area nozzle such that fluid enters the vertical pipe tangentially to the cross-section of the vertical pipe. The reducing area nozzle increases the fluid velocity as the fluid enters the vertical pipe, thus creating a cyclone or swirling motion of the fluids to be separated. The higher density fluid tends to flow centrifugally along the inner surface of the vertical pipe and exits through the bottom of the separator, while the lower density fluid tends to flow centrally and exits through the top of the separator.
The horizontal inlet of the LLCC© is an important component of the separator, in which stratification of the two phases in this region can be promoted to improve phase separation. The geometry of the horizontal inlet is also responsible for generating the centrifugal forces which enhance phase separation. However, in practice, it has been found that the stratified fluid phases can become mixed in the cyclone, thus negatively affecting separation of the fluids.
It would be desirable to improve the phase separation of liquid-liquid cylindrical cyclone type separators.